Detect git lfs pointer files

[pombredanne]

These are small placeholders that are fetched from another place using git lfs. They have the same name and path as the full file.
For instance:

version https://git-lfs.github.com/spec/v1
oid sha256:6fd5d72fe4589f189f8ebc006442dbb529bb7ce38f8082112682524616046452
size 90405214

The .gitattributes file of a repo also has some config:

*.7z filter=lfs diff=lfs merge=lfs -text
*.bin filter=lfs diff=lfs merge=lfs -text
...

It is not clear how to fetch these files short of using git lfs.